Complex process sequences having a plurality of lithography steps are required for manufacturing integrated circuits. Auxiliary lithography structures in every mask level are produced in the process steps in the substrate in which the integrated circuit is also manufactured. These auxiliary lithography structures are employed for the alignment of the next mask level as well as for the evaluation of the process steps. The auxiliary lithography structures are thus subject to the same process influences as the structures of the integrated circuit to be manufactured (see, for example, S. Wolf et al., Silicon Processing for the VLSI-Eras, Lattice Press, 1987, pp. 473-476).
Trench structures are being increasingly employed in circuit arrangements having an increased packing density. Among other things, such trench structures are filled with insulating material and are utilized as insulating trenches for insulation between neighboring circuit elements, for example between bipolar transistors or between power components and logic components. The trench structure is etched into the substrate. The auxiliary lithography structure is likewise subjected to the trench-etching process in the manufacture of the trench structure.
When the auxiliary lithography structures are broader than the trench structures--this being frequently the case in current technologies--a complete filling of the auxiliary lithography structures does not occur when filling deep trenches. The surface of the structure then comprises steps in the region of the auxiliary lithography structures, these steps leading to the fact that a reliable process management suitable for fabrication is no longer possible. This problem is especially serious in smart power technology on SOI material. Logic components and power components that are each respectively surrounded by an insulating trench that extends onto the surface of the insulating layer are thereby realized in a single-crystal silicon layer that is arranged on an insulating layer (see, for example, A. Nagakawa et al., ISPS 1990, pp. 97-101). In this employment, trench structures having widths of 1-3 .mu.m and depths from 20-30 .mu.m arise. Auxiliary lithography structures, whose geometry is usually prescribed by the apparatus manufacture, by contrast, comprise widths in the range from 3-30 .mu.m.